As layout structures of a fuel pump of a motorcycle, Japanese unexamined patent publication No. 2000-297711 discloses a structure in which a fuel pump is disposed near an engine. Japanese unexamined patent publication No. 2002-106440 discloses a structure in which a fuel pump is disposed in a fuel tank
The structure disclosed by publication No. 2000-297711 will be described with reference to FIG. 5 and the structure disclosed by publication No. 2002-106440 will be described with reference to FIG. 6.
FIG. 5 is a cross section showing a conventional layout structure of a fuel pump of a motorcycle and illustrates that a fuel case 103 in which a fuel pump is housed is disposed above an engine 101 and below a fuel tank 102. The layout includes a throttle body 105, and a fuel injection valve 106 attached to the throttle body 105. The fuel case 103 is shown not in a cross section but in a side view for convenience. The fuel case 103 for housing the fuel pump is disposed near the engine 101, so that the fuel case 103 is easily heat-affected. When the fuel case 103 is disposed near the fuel tank 102, the degree of freedom of connection between the fuel case 103 and the fuel tank 102 decreases, and a processed shape of a bottom wall of the fuel tank 102 becomes complicated.
FIG. 6 is a cross section showing another conventional layout structure of a fuel pump of a motorcycle. A mounting flange 112 is attached to an inner surface of a fuel tank 111. A center portion of the mounting flange 112 is covered with a base plate 113, a strainer 114 is attached to the base plate 113, a fuel pump 115 is coupled to the strainer 114, and a fuel filter 116 is connected to the fuel pump 115. When the fuel pump 115 is attached in the fuel tank 111, the degree of freedom of attachment of the fuel pump 115 is limited by the shape of the fuel tank 111. Particularly, in an American-type vehicle having the flat fuel tank 121 shown in FIG. 7, the shape and dimensions of the fuel pump apparatus 123 are also limited.
FIG. 7 shows a layout structure of a fuel pump in an American-type motorcycle. FIG. 7 is a partly-sectional side view showing a conventional layout structure of a fuel pump of a motorcycle. A fuel tank 121 of an American-type motorcycle (a vehicle called a “custom vehicle”) has a thin and flat shape having a large dimension in the longitudinal direction and a small dimension in the vertical direction (so-called a teardrop (water drop) shape). FIG. 7 shows that a fuel pump apparatus 123 which includes a strainer, a pump body, and a motor and is long in the longitudinal direction is attached to an inner wall 122 of the fuel tank 121.
An object of the invention is, therefore, to improve a layout structure of a fuel pump of a motorcycle, thereby increasing resistance to thermal effects of an engine, facilitating connection to a fuel tank, and increasing the degree of freedom of layout for a vehicle body.